Tube expander and method of expanding tubes



July 7, 1931. K. A. STENNER 1,813,096

TUBE EXPA NDER AND METHOD OF EXPANDING TUBES Filed Aug. 14, 1929 Patented Jul 7, 1931 UNITED s'rarl-z'smm. A. swarm or Inmate commcricu'r" 'ruBn mmna AND METHO on runs Application filed August 14', 1920. septuso; m.

My invention relates to the class of devices used for the purpose of enlarging tubes, and an object of my invention, among others, s the production of a device that shall be particularly efiicientfor the purpose for w it is designed.

One form of my improved expander in the i use of which the objects herein set out, as well as others, may be attained, is illustrated in the accompanying drawings, in which- Figure 1 is a view in'lengthwise section through a tube with my improved expander therein shown preparatory to the operation of securing fins or plates in spaced relation 6 along said tube, parts being broken away to show construction.

Figure 2 is a similar view, scale enlarged, showing the operation of the device. Figure 3 is an isometric view of the expand-V sleeve. y improved expander, while not limited in its use for expanding tubes for any particular purpose, yet, as it is particularly adapted for use in the construction of radiators, they have been employed herein for the purpose of disclosing the invention, in the accompan ing drawin s the numeral 5 indicating a tu e and 6 radiating fins or plates commonly employed for con uction purposes in connection with said tube, a number of the' latter being usual embodied in a single structure. It has heretofore been common practice to swell such tubes for the purpose of sev curing the fins in place and my improve implement forming the subject-matter of this application is peculiarly adapted for this purpose, this implement or tool comprising an expanding bushing 7 and a ta ered ex-' panding mandrel 8 adapted to t within the bushing. The hole through the bushing is tape to correspond with the red taper of the mandrel and the bushing is split, in the preferred form slots 9 being extende inwardly from one end nearly to the opposite end and alternate slots being extended from opposite ends of the bushing. In a preferred construction I prefer to extend one slot, as 10, from end to end of the bushing.

It may here be remarked that while in some cases a single mandrel and a single bushing hieh j.

d to place-the may belemployed, yet, in many cases a plurality of such -members will be required. With this arrangement it will be found of advantage to; have each mandrel longer than 7 Its companion'bushing andto em loy spacers 11 to separate the-bushings to t e required extent, these spacers having central openings therein largexeno'ugh to receive the larger end of the mandrel". In the useflofthe device the fins having been placed upon a tube or tubes and retained suita 1y spaced thereon in any desired manner, and the expanding devices being within the tube or tubes, the mandrel or mandrels are forced lengthwise .into the bushings, the mandrels abutting each against another, and to facilitatethe relative ositionin of the mandrels each is provided: preferabIy-at its larger end, with a recess and at its opposite end with a pro ection 12-shaped to fit the re cess 1n the end of the adjacent mandrel.

When the mandrels have been forced inwardly to a sufiicient extent by applyin force to the larger end of the outer man-dre the tube 5 will have been expanded at the points engaged by the bushings to secure the fins or plates tightly in place, and as shown in Figure 2 in which this expansion is shown to an exaggerated de ree. With the parts arranged as shown-in igure 2, one expand-' ing operation having been effected, the mandrels are loosened by forcing them backwardly and the bushings and spacers are shifted bushings in the locations before the spacers and a second opera unexpanded occupied b tion is per ormed to expand the portions of the tube.

In accordance with the provisions of the patent statutes I have described the principles of operation of my invention, together with the device which I now'consider to represent the best embodiment thereof; but I d desire, to have it understood that the device shown is only illustrative, .and the invention may be carried out by other means and applied to uses other than those above set out.

1. A tube expander including a tapered mandrel, a plurality of bushings outwardly shaped to fit a tube and inwardly shaped to fit a mandrel, and a spacer located between said bushings.

2. A tube expander including a plurality of tapered mandrels, a pluralit o tapered bushin s outwardly shaped to t a tube and inwanfiy shaped to fit a mandrel, said bushings bein shorter in length than said mandrels, an a spacer located between each two adjacent bushings.

3. A tube expander including a tapered mandrel provided at its ends with means to receive and position an abutting mandrel, a plurality of bushings outwardly shaped to fit a tube and inwardly shaped to fit a mandrel, and a spacer interpose between each two adjacent bushings.

4. The process of expanding a tube into tight contact with surroundin fins, that consists in placing within said tu a number of expansible bushings outwardly shaped to fit said tube, locating a spacer between each two adjacent bushings, placing a number of tared mandrels fitted to holes within said giishings and applying force to the larger end of the outer mandrel.

5. A tube expander including a tapered mandrel, a plurality of bushin s outwardly shaped to fit a tube and inwardly shaped to fit a mandrel, and a spacer located between said bushings and having an opening therein large enough to receive the arger end of y the mandrel.

6. A tube expander including'a tapered mandrel, and a tubular structure extending to the end of a tube to be operated upon,"said tubular structure including a plurality of bushings outwardly shaped to fit a tube and inwardly shaped to fit a mandrel.

7. A tube ex ander including a tapered mandrel, provi ed at its ends with means to receive and position an abutting mandrel, and a plurality'of bushings butwardl' to fi't'a tube and inwardly shaped to t a mansists in drel..

8. The process of expanding a tube into tight contact with surrounding fins, that con placing within said tube a number of expansi le bushings outwardly shaped to -fit said tube, placing a spacer betweeneach two adjacent bushings, placing a number of tapered mandrels fitted .to holes within said ushing's, applying force to the larger end of the outer mandrel, loosening the mandrels, moving the mandrels and bushings endwise wit; in the-tube to new positions, and again applyin force to the larger end of the outer mandre KARL A. STENNER.

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